PennDOT Roundabout Guidance—Benefit-Cost Spreadsheet

KAI is developing a spreadsheet for the Pennsylvania Department of Transportation (PennDOT) that computes the life-cycle cost of various intersection forms. The spreadsheet will be used by PennDOT to compare roundabouts with traditional intersections. It will assist with the selection of intersection control on a site-by-site basis. The methodology considers the economic cost of delay (lost productivity) incurred by persons in vehicles; operations and maintenance costs; and capital planning, design, and construction (direct user inputs). The frequency and severity of crashes, and the corresponding cost, is computed by the spreadsheet, using the methodology of the Highway Safety Manual. Operations and maintenance costs are also computed by the spreadsheet. Separate methodologies are used to compare two intersection forms at a new intersection, replacement of an existing intersection with a roundabout, and roundabout and traditional form improvements at an existing intersection.